Serial Port - Sierra Wireless AirLink GX450 Hardware User's Manual

AirLink GX450 Hardware User Guide
AirLink GX gateway
I/O Circuit
Pin 4 is normally at 3.3 V,
but is pulled low
when activated.
Figure 2-22: Digital Output Operation
Note: Some solenoids/relays include a flyback diode built into the unit. For those that do not, Sierra
Wireless recommends a flyback diode with a voltage rating at least double the relay voltage and a
current rating at least double the relay ON current to avoid damage to the GX input. A common
1N4007 will work for most applications. See
The initial state of the digital output when the gateway is rebooted is configurable in
ACEmanager.

Serial Port

You can connect the GX450 gateway's 9-pin serial connector directly to most computers
or other devices with a standard straight-through cable. This connector is used for
gateway configuration and debugging.
This connector complies with the EIA RS-232D specification for DCE equipment. The
output driver levels swing from -7 VDC to +7 VDC with normal loading.
Note: If you have a DCE device, you need to use a null modem cable.
Rev. 11 July 2019
3.3 V
Voltage supply
51 k
internal
pull up
CL+
Flyback diode
CL-
External Solenoid/Relay Circuit
(Exact voltages and configuration
depend on the actual system design.)
Table 2-7 on page 40.
36
COM
NC
NO
4114008